System and Method for Thermal Ablation of Pigging Devices

ABSTRACT

The present disclosure provides for a novel pig design and method of retrieval based on thermal ablation. The pig comprises an external layer and an inner core, where the inner core further comprises at least one incendiary charge comprising at least one exothermic material. When ignited via an ignition source, the incendiary charge releases the exothermic material into one or more thermal dispersion channels. The exothermic material melts the interior of these thermal dispersion channels thereby distributing the exothermic material throughout the pig device causing its destruction via thermal ablation. The destroyed pig can then be easily retrieved from its location in a pipe, as detected via radio signals, without the need for costly excavation of large sections of the pipe.

RELATED APPLICATIONS

This Application claims priority under 35 U.S.C. §119(e) to pending U.S.Provisional Patent Application No. 62/184,981, filed on Jun. 26, 2015,entitled “System and Method for Thermal Ablation of Pigging Devices,”which is hereby incorporated by reference in its entirety.

BACKGROUND

Pigging is used as a mechanism to clean internal surfaces of pipelinesincluding sewer, process, water, wastewater and other types of pipes.Pigging is used to reduce the friction losses of pumping energy, improveflow rates of restricted piping, and as a general maintenance process.Typical materials of construction for water pipe and municipal,commercial, and industrial sewer pipe include ductile iron, polyvinylchloride (“PVC”), and lined ductile iron or cast iron pipe. As sewerforce mains are used over time, the flow of sewage is restricted by abuildup of restricting materials on the inside of the pipe. Thismaterial includes solid waste, grease, pipe corrosion and othermaterials. In addition to these restrictions, force sewer mains, whichwere installed years and sometimes generations ago, are used to carryflow in excess of their original design capacity. As the pipe isrestricted over time, the pumping horsepower requirement increases, flowis reduced, and electrical energy consumption of the pump is increased.

Pigging is the process of inserting a device (known commercially as apig) into the pipe through an insertion point installed at a particularlocation in the pipe. The insertion point is generally referred to as alaunch station, and includes an array using a tee, valving, and apressure injection point to allow the pig to be inserted into the pipeand then propelled through the pipe via motive force which may be water,steam or compressed air. Once inserted, the pig is propelled through thelength of pipe, which is typically underground, to a designated removalpoint. While traversing the pipe the pig scours the inner wall of thepipe, without damaging the pipe, to remove any flow restrictingmaterial.

Pig construction is generally of polyurethane foam, with or without anabrasion resistant cover. Alternate pig materials of the prior artinclude Styrofoam, polypropylene, and ice. Various abrasive coatings mayalso be used and brushes may be adhered or fastened to the bearingsurfaces (where the pig is in contact with the pipe wall). Theseabrasive coatings and brushes aid the pig in clearing debris from theinterior of the pipe.

Currently, pigging utilizes a process of progressive pigging, whereinseveral pigs of varying diameters, all being smaller in overall outsidediameter than the nominal inside diameter of the pipe, are used toinsure that no obstruction which would cause the pig's progress thoughthe pipe to be impeded to the point of the pig being stalled or stuck inthe pipe. Once a smaller diameter pig has successfully traversed thelength of pipe being cleaned, a slightly larger pig is inserted, and theprocess repeated until near nominal internal pipe diameter is reached,or obstruction of the pipe becomes a risk. During the pigging processthe pressure of the propulsion medium is monitored continuously. So longas the pig is traveling through the pipe, the pressure remains at aconstant level, plus or minus a predetermined tolerance. As fluid or gasis injected into the pipe, the pig travels through the pipe increasingthe effective volume filled by the propulsion media, resulting inrelatively constant pressure. If the pig movement stops, the volumebehind the pig within the pipe no longer increases, and as propulsionmaterial is added the pressure within the pipe will rise rapidly.

A stalled or stuck pig represents a significant technical and logisticalproblem. The overwhelming majority of wastewater and sewage piping isinstalled underground. Based on the age and location of the pipe, aswell as potential interference with other utility piping, the effect onother electrical and telecommunication utilities by a stuck or stalledpig is largely unknown. Even in a scenario where the exact pipe locationis documented, the exact pig location within the pipe may still beunknown.

As a result, the location and retrieval of a stalled pig can beincredibly costly. Often, the retrieval requires a utility shutdown, adiversion of sewage via multiple vacuum trucks at sewage interceptors,and coordination with municipal and utility entities to divert trafficflow and coordinate utility shutdowns while excavation and removal ofthe stuck pig occurs. In such a case, the only method to remove astalled pig is to begin excavating the pipe. Due to the fact that theexact location of the stuck pig is unknown, multiple excavations may berequired until the exact location of the stalled pig is determined andsuccessful removal of the pig is achieved.

As an alternative to progressive pigging, and in an attempt to mitigatethe risk and cost of a stalled or suck pig, a process of pigging hasbeen modified to use pigs made of ice or gelatin. Pigs made of thesematerials will degrade and break down as the pig travels the length ofthe pipe. This modification substantially eliminates the risk of astalled pipe since the pig will melt or erode as it passes through thepipe. Pigs made of ice will continue to melt even after the pig becomesstalled or stuck in the pipe. The erosive nature of pigs made of thesematerials often eliminates the problem with no need for excavation ofthe pipe or other remedial action. Unfortunately, the overall dimensionof the ice or gelatin pig begins to decrease as soon as the pig isinserted into the pipe. As the pig traverses the length of the pipe, thereduction in overall dimension continues, resulting in a reduction ineffectiveness of the ice or gelatin pig as the pig travels the length ofthe pipe. Ultimately, use of an ice or gelatin pig for long distancepigging is of very little if any benefit.

There exists a need for a novel pig design that substantially reducesthe risk of the pig being stuck or stalled in a pipe and which can beretrieved without substantial additional risk or cost. It would also beadvantageous if the novel pig design improved and maintained theeffectiveness of the pig as it travels the length of the pipe, therebyimproving current methods for pigging of long distance pipelines.

SUMMARY OF THE INVENTION

The present disclosure provides for a novel pig design and retrievalmethod based on thermal ablation. The pig is constructed with acorrectly engineered incendiary charge corresponding to the size,density, and the materials of construction of both the pig and the pipein which the pig will be used. The incendiary charge is correctly sizedso that the pig is sufficiently destroyed upon ignition to allow anyremaining components or residue in the pipe to be passed through thepipe without the need to excavate the pipe to retrieve the pig. The pigmay be designed to be destroyed automatically, manually, or by acombination of automatic control with manual override of the incendiarycharge.

In one embodiment, the present disclosure provides for a pig devicecomprising an external layer and an inner core made of polyurethanefoam. The inner core may further comprise at least one incendiary chargewherein each incendiary charge further comprises at least one exothermicmaterial. At least one ignition source may be coupled to each incendiarycharge and be configured so as to ignite the associated incendiarycharge. A plurality of thermal dispersion channels may be arranged inthe inner core to enable the exothermic material to evenly propagatethrough the pig device and cause its destruction. One or more switchingmechanisms may be configured to control the activation of the ignitionsource thereby controlling the release of the exothermic materialthrough the pig device.

In another embodiment, the present disclosure provides for a method forthermally ablating a pig device. This method may comprise providing apig device comprising an external layer and an inner core, wherein theinner core comprises one or more incendiary charges and wherein eachincendiary charge further comprises one or more exothermic materials.The ignition source, which is operably coupled to an incendiary charge,may be ignited, to thereby release the exothermic material into one ormore thermal dispersion channels. The interior of each thermaldispersion channel is melted to thereby disperse the exothermic materialthrough the inner core and thereby destroy the pig device.

In another embodiment, the present disclosure provides for a method forretrieving a pig device which is destroyed using thermal ablation. Themethod may comprise first locating the pig device within a pipeline bydetecting radio signals emitted by a radio receiver located within thepig device. Once the pig device has been located, the method may furthercomprise igniting at least one ignition source, wherein each ignitionsource is operably coupled to an incendiary charge, to thereby releaseat least one exothermic material into one or more thermal dispersionchannels. The interior of each thermal dispersion channel is melted tothereby disperse the exothermic material through the inner core of thepig device and thereby destroy the pig device. The destroyed pig maythen be easily retrieved at its detected location.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide furtherunderstanding of the disclosure and are incorporated in and constitute apart of this specification, illustrate embodiments of the disclosureand, together with the description, serve to explain the principles ofthe disclosure.

In the drawings:

FIG. 1 is representative of a pig of the present disclosure.

FIG. 2A is representative of a side view of a pig of the presentdisclosure.

FIG. 2B is representative of a front view of a pig of the presentdisclosure.

FIG. 3A is representative of a side view of the switching mechanisms andcharge configurations of the pig device of the present disclosure.

FIG. 3B is representative of a front view of the switching mechanismsand charge configurations of the pig device of the present disclosure.

FIG. 4 is representative of a method of the present disclosure.

FIG. 5 is representative of a method of the present disclosure.

FIG. 6 is representative of a base of a pig device of the presentdisclosure with an inner core made of polyurethane foam.

FIG. 7 is representative of an incendiary charge used in a pig of thepresent disclosure with two igniters.

FIG. 8 is representative of a pig device loaded with an incendiarycharge.

FIG. 9 is representative of a pig device loaded with a radio receiver.

FIG. 10 is representative of a pig device ablated using the methodsdescribed herein.

FIG. 11 is representative of a pig device ablated using the methodsdescribed herein.

FIG. 12 is a thermal image illustrating heat emitted by a pig deviceduring ablation.

FIG. 13 is a thermal image illustrating heat emitted by a pig deviceduring ablation.

FIG. 14 is a thermal image illustrating heat emitted by a pig deviceduring ablation.

FIG. 15 is representative of a pig device of the present disclosureinserted into an exemplary pipe during testing.

FIGS. 16A-16C illustrate the dimensions of a rock used as an obstructionin experimental designs used to test the effectiveness of a pig deviceof the present disclosure. FIG. 16A shows the width of the rockobstruction as being approximately four inches. FIG. 16B shows thelength of the rock obstruction as being approximately seven inches andFIG. 16C shows the height of the rock obstruction as being approximately2.5 inches.

FIG. 17 is representative of a pig device of the present disclosureinserted into an exemplary pipe during testing showing an obstruction.

FIG. 18 is representative of a pig device of the present disclosureinserted into an exemplary pipe during testing showing an obstruction.

FIG. 19 is representative of a pig device of the present disclosureinserted into an exemplary pipe during testing showing an obstruction.

FIG. 20 is representative of the interior of a pipe after ablation of apig device using the methods described herein.

DETAILED DESCRIPTION

Reference will now be made in detail to the preferred embodiments of thepresent disclosure, examples of which are illustrated in theaccompanying drawings. Wherever possible, the same reference numberswill be used throughout the drawings to refer to the same or like parts.

The pig device of the present disclosure overcomes the limitations ofthe prior art by providing a novel design for easy location,destruction, and retrieval of the pig using thermal ablation techniques.Referring to FIG. 1, the pig device 100 may comprise an external layer110 and an inner core 115. In one embodiment, both the external layer110 and the internal core 115 may comprise a polyurethane foam material.Constructing the pig device 100 using a polyurethane material isadvantageous over the designs of the prior art that use materials suchas gelatin or ice. Where pigs constructed using gelatin or ice degradeas the pig travels the length of a pipe, the polyurethane pig of thepresent disclosure maintains it size, and therefore its efficacy, untilit is deflagrated in accordance with the methods disclosed herein. Theexternal layer 110 may further comprise an abrasive-resistant coverconfigured to protect the pig device from damage as it travels thelength of a pipe and one or more abrasive coatings or brushes configuredto clear debris from interior of the pipe.

Referring again to FIG. 1, the pig device 100 may comprise at least oneincendiary charge 120 a where each incendiary charge comprises one ormore exothermic materials. When the incendiary charge 120 a is ignitedby an ignition source, the exothermic materials are released into aplurality of thermal dispersion channels 125 a-125 d. The thermaldispersion channels are designed so as to prevent water or othermaterials from entering the inner core of the pig device and disruptingor preventing the ignition process. In one embodiment, thermaldispersion channels 125 a-125 d may be filled with a material, such asparaffin wax, which melts upon the ignition of the incendiary charge andprovides channels for the exothermic material to evenly disperse throughthe pig device. This dispersion of the exothermic material causes thepig device to deflagrate so that it can be easily retrieved from thepipe. In other embodiments, any hydrophobic material with a low meltingpoint may be used to fill the thermal dispersion channels. One exampleof a material that may be used as an alternative to paraffin wax isheavy grease. The thermal dispersion channels may also be left unfilled.In such an embodiment, the ends of these thermal dispersion channels maybe plugged with a room temperature vulcanizing sealant to prevent waterand other materials from entering the inner core.

Ignition of the incendiary charge 120 a may be achieved via one or moreswitching mechanisms 130. These switching mechanisms are known in theart and may include at least one of: a manual hardwired switchingmechanism, a manual radio controlled switching mechanism, and anautomatic pressure sensing switching mechanism. An exemplary design ofthe switching mechanism 130 is illustrated in more detail in FIG. 3A andFIG. 3B. FIG. 3A is representative of a side view of the various chargesand switching mechanisms contemplated by the present disclosure whileFIG. 3B is representative of a front view of these various mechanisms.While the embodiment of FIG. 3A and FIG. 3B illustrate the pig device100 as comprising all three switching mechanisms, it is noted that notall three switching mechanisms are required and other embodiments mayutilize only one or two of the illustrated switching mechanisms. Amanual hardwired switching mechanism 130 a may be used to fire the pigdevice 100 via tether wire connected directly to the pig firing controlsand fed into the pipe via a wire reel setup at the launch station. Thisfiring control configuration is best suited as a manual backup to theautomatic firing control system which may be onboard the pig. Bestapplications for this switching mechanism include firing in a deeplyburied or extremely long pipe where the approximate location of the pigmay be difficult to determine. This manual hardwired switching mechanism130 a is also useful for ablating a pig located within a ductile ironpipe which is impervious to radio frequency signals.

A manual radio controlled switching mechanism 130 b may be used to firethe pig device 100 via a remote control with a radio receiver mounted onboard the pig. In one embodiment, the radio receiver may comprise anattendant 9 volt battery. Manual radio remote control firing alone isapplicable to scenarios where adequate pressure control and regulationis not available or practical, or pipe distance is relatively short,allowing the operator the ability to walk the length of the pipe,generating multiple ignition requests.

A pressure sensing switching mechanism 130 c may be used to fire the pigdevice 100 by sensing when a set pressure has been reached. For examplewhen the pressure on the pressure sensing switching mechanism 130 creaches a specified level due to a propulsion material added to thepipe, the switch will close an electrical contact and cause theincendiary charge 120 a to fire. Igniters 127 a-127 e may be wired inparallel and operably coupled to the incendiary charge 120 a andfunction to ignite the incendiary charge 120 a. As can be seen in FIG.3A and FIG. 3B, these igniters 127 a-127 e may be placed at variouslocations around the incendiary charge 120 a. A radio receiver, tolocate the pig device 100 within a pipe, and radio receiver and powersource 135 may also be located with in the inner core 115 of the pigdevice 100. In one embodiment, the power source 135 may comprise one ormore batteries.

FIG. 2A and FIG. 2B are illustrative of another embodiment of the pigdevice 100 of the present disclosure. As seen in FIGS. 2A and 2B, thepig device 100 comprises a plurality of incendiary charges 120 a-120 hconfigured in a circular arrangement (which can be seen from the frontview of the pig device 100 in FIG. 2B) in the inner core 115. It isnoted that any number and any arrangement of the incendiary charges maybe used based on the size of the pig device 110 as necessary to achievethe ablation of the pig device 100. As seen in FIG. 2A each incendiarycharge 120 a-h is coupled to a thermal dispersion channel 125 a-125 h toensure the exothermic material is evenly distributed throughout the pigdevice 100. This coupling between each incendiary charge 120 a-h and thethermal dispersion channels 125 a-125 h is further illustrated in FIG.2B.

The present disclosure also provides for a method for thermally ablatinga pig device, one embodiment of which is illustrated in FIG. 4. Themethod 400 may comprise providing a pig device comprising an externallayer and an inner core, wherein the inner core comprises one or moreincendiary charges and wherein each incendiary charge further comprisesone or more exothermic materials in step 410. An ignition source,operably coupled to each incendiary charge, may be ignited in step 420to thereby release the exothermic material into one or more thermaldispersion channels. The interior of each thermal dispersion channel ismelted in step 430 by the exothermic material which enables theexothermic material to propagate through the pig device therebydestroying it by thermal ablation.

In another embodiment, the present disclosure provides for a method forretrieving a pig device that has been ablated using the methodsdisclosed herein. Such a method 500, illustrated by FIG. 5, may compriselocating the pig device within a pipeline using radio signals detectedfrom a radio receiver located within the pig device in step 510. In step520, at least one ignition source may be ignited, wherein each ignitionsource is operably coupled to an incendiary charge. Once ignited, theincendiary charge releases at least one exothermic material into one ormore thermal dispersion channels. The interior of each thermaldispersion channel may be melted in step 530 to disperse the exothermicmaterial through the inner core and thereby destroy the pig device. Thepig may be retrieved in step 540 at the detected location within thepipe.

EXAMPLES

The following example details experiments designed and implemented usingthe pig device and ablation methods of the present disclosure. FIGS.6-20 illustrate an exemplary pig design used in the experimental set updescribed herein. FIG. 6 illustrates the base of a pig device with apolyurethane foam inner core. An incendiary charge with two igniters isillustrated in FIG. 7 and FIG. 8 illustrates this incendiary chargeloaded into the base of the pig device. The radio receiver is shownloaded into the pig device in FIG. 9.

Testing results show that the materials and devices consistent withcommercial pipe pigging may be effectively ablated or destroyed in placewithin the pipe to consistently allow materials to be flushed from thepipe past or through significant obstructions using water as a motiveforce. Due to the combustion process of the methods of the presentdisclosure, water as the motive force is the only method which may beused in this method of thermal ablation as the water acts a heat sinkfor the process and effectively protects the pipe from damage. Testingshows that class 200 PVC pipe exhibited zero thickness loss, zero pipewall distortion and a maximum external temperature of 8.7° F. over theinside of the pipe when surrounded by air. Testing shows pipediscoloration from products of combustion but no surface erosion due tothe combustion process. The interior of a pipe after ablation of a pigdevice using the methods described herein in FIG. 20.

FIGS. 15-20 illustrate the experimental design set forth herein. In FIG.15, the pig device is inserted into a pipe. The dimensions of a rockused as an obstruction in this experimental design are set forth inFIGS. 16A, 16B, and 16C. FIG. 16A shows the width of the rockobstruction as being approximately four inches. FIG. 16B shows thelength of the rock obstruction as being approximately seven inches andFIG. 16C shows the height of the rock obstruction as being approximately2.5 inches.

To deflagrate the pig via chemical means in an environment devoid ofoxygen gas, such as a pipe, requires utilizing oxidizing agents toprovide the necessary oxygen atoms to the system. In this specific casethe exothermal reagents must continue to burn even when submerged inwater. To accomplish this, a modified form of Ellern's formulationnumber 36¹ was used which utilizes magnesium and aluminum for fuels withbarium sulfate and barium nitrate serving as the oxidizing agents.

The formulation of Ellern was originally intended to be used inunderwater flares and therefore holds potential for the presentinvention. It is, by mass, 16% magnesium, 12% aluminum, 32% bariumnitrate, and 32% barium sulfate with an unspecified amount of manganeseoxide mixed in with linseed oil to form a binder. With these mass ratiosthe barium sulfate and barium nitrate are together limiting reactants.Experiments have shown that use of Ellern's formulation will result indifficulty starting the main reaction. It was assumed that the manganeseoxide was part of a thermitic reaction to help achieve the activationenergy needed to initiate the main reaction. The manganese oxide wasremoved from the reaction and replaced with stoichiometric amounts ofaluminum and iron (III) oxide added prior to combining with the binder.The Al/Fe₂O₃ reaction is also known to have a relatively low ignitionpoint and be highly exothermic, thus helping to both start the reactionand sustain the high burn temperature needed underwater. The followingamounts of each material were used in the present experimental design:

Modified Formulation: (% Composition by Mass)

Magnesium 12.1% Aluminum 15.2% Barium Nitrate 24.2% Barium Sulfate 30.3%Iron (III) Oxide 18.2%

To prepare the exothermal mixture atomized aluminum and 325 meshgranular magnesium were combined with powdered forms of the oxidizersand homogenized. The homogenized granular powder was then compoundedwith pure, unboiled, linseed oil (ρ=0.93 g/ml) using 6 ml of linseed oilper hundred grams of powder to form the material for the charge. The pigdevice and methods of the present disclosure are not limited to theseconcentrations. It is contemplated that the following workable ranges ofmaterials may be used (% composition by mass): barium nitrate from about22.5% to about 27.5%; barium sulfate from about 25.3% to about 33.5%;iron (III) sulfate from about 14.8% to about 19.4%; aluminum from about12.8% to about 15.8%; and magnesium from about 10.4% to about 13.5%.

Approximately 210 grams of the exothermal material was packed into ahollow cardboard tube (1.75″ diameter, 4.24″ long). It is noted thatother materials may be used to house the exothermal material includingbut not limited to glass and plastic. To help insure that the materialignited, a small disk (approximately ⅛″ thick and approximately 1″ indiameter) of secondary ignition material (described herein) was placedon top of the exothermal material and a commercially availablepyrotechnics igniter was then placed on top of the secondary ignitionmaterial. Cloth medical tape was used to securely fasten the igniter tothe ignition material and to seal the end of the tube. It iscontemplated that other types of tape or other mechanisms may be used solong as the mechanism securely fastens the igniter and the ignitionmaterial and to seal the end of the tube. The cloth tape was then usedto secure the igniter wire to the long axis of the tube for stressrelief and to ensure that the igniter was not pulled away from theignition material. This process was repeated on the other end of thecharge; each charge has two ignition points (See FIG. 7).

In early tests the commercially available igniters were not alwayscapable of starting the reaction for the primary charge. A secondaryignition charge made of sucrose and potassium nitrate was added betweenthe commercially available igniter and the main charge. The secondarycharge was made by mixing 65% potassium nitrate with 35% sucrose; thisis a mixture commonly found in model rocketry. The mixture wasthoroughly homogenized and then carefully heated (to approximately 160°C.) until the sugar oxidized, turned light brown, and underwent a phasechange to form a paste. The paste was then spread on wax paper atapproximate ⅛″ thickness for cooling. Once re-crystallized, the materialwas broken into appropriate sized pieces and shaped for use as thesecondary ignition material.

There are five heat producing oxidation-reduction reactions used in thisdevice. Reaction enthalpies at 298K were determined by using standardenthalpies of formation² and the state law equation. In addition theheat liberated per gram of reactant was also computed.

These values are in rough agreement with values found in the literaturewhich listed 1400 cal/g for reaction 1 and 900 cal/g for reaction 2.³Since the entire mixture is homogenized before adding the linseed oilbinder it is assumed that the oxidizers are equally available to theirpertinent reactions. As such one may further assume that half of each ofthe Ba(NO₃)₂ and BaSO₄ oxidizers goes to each of the fuels. In thisformulation the oxidizers are the limiting reagents and can therefore beused to stoichiometrically compute the amount of fuel needed and theamount of energy produced by each reaction as seen in Table 1.

TABLE 1 Assuming starting masses of 32 g Ba(NO₃)₂, 40 g BaSO₄, and 24 gof Fe₂O₃. Reaction Oxidizer Mass Stoichiometric Fuel Mass Energy fromRxn 1 16 g Ba(NO₃)₂ 5.51 g Al 34400 cal 2 20 g BaSO₄ 4.62 g Al 15600 cal3 16 g Ba(NO₃)₂ 7.44 g Mg 37700 cal 4 20 g BaSO₄ 6.24 g Mg 18400 cal 524 g Fe₂O₃ 8.11 g Al 30400 cal Total 127.9 g (132 g if including excessfuel) 136500 cal 

Using these totals the energy generated per gram of starting material is1040 cal/g (or 4.13 btu/g). The PIG is made of a polyurethane corematerial. Polyurethane foams have approximate heats of combustion of2400 cal/g (9.52 btu/g)⁴. To completely destroy a pig device wouldtherefore require using approximately 2.3 g of exothermic reactants foreach gram of polyurethane to be deflagrated.

A low density polyurethane pig device enclosing 210 grams of exothermalreactants described above was ignited while submerged in 20 gallons ofwater. FIGS. 17, 18, and 19 illustrate the pig undergoing the reactionsdescribed herein. Theoretically, the exothermal reaction should liberateat most 867 btu of energy and increase the temperature of the water by5.18° F. The temperature of the water was measured via a thermal imagerprior to and immediately after the reaction completed as illustrated inFIGS. 12-14. A temperature change of approximately 5° F. was recorded.As such, and within the experimental error of the measuring devices, thethermochemistry described above is consistent with the observedexperimental results.

There are numerous exothermal reagents and combinations of exothermalreagents that could be used to accomplish the pig deflagration. Thisapplication lays claim to the idea of using an exothermal agent todestroy the pig. In the chemical reactions described above the followingoxidations take place: Mg⁰→Mg^(II) and Al⁰→Al^(III). The reductions areN^(V)→N⁰, S^(VI)→S⁰, and Fe^(III)→Fe⁰. Because of their location in theactivity series with respect to magnesium and aluminum, several activemetals (lithium, potassium, strontium, calcium, sodium) could replacebarium as the cation in the oxidizing agents. Similarly, numerouspolyatomic ions could potentially be used instead of nitrate andsulfate. The choices of barium nitrate, barium sulfate, and iron (iii)oxide for the prototype device described herein were primarily based onseveral factors including: (i) the similarity to Ellern's originalformulation; (ii) their known characteristics within the pyrotechnicsindustry; (iii) being readily available from numerous manufacturers; and(iv) the high burning point and insolubility of barium sulfate in water.

The present disclosure may be embodied in other specific forms withoutdeparting from the spirit or essential attributes of the disclosure.Accordingly, reference should be made to the appended claims, ratherthan the foregoing specification, as indicating the scope of thedisclosure. Although the foregoing description is directed to theembodiments of the disclosure, it is noted that other variations andmodification will be apparent to those skilled in the art, and may bemade without departing from the spirit or scope of the disclosure.

REFERENCES CITED

-   1. Ellern, Herbert. Military and Civilian Pyrotechnics. (New York:    Chemical Publishing Company, 1968).-   2. CRC Handbook of Chemistry and Physics, 62nd ed. Robert C. Weast    and Melvin J. Astle, eds. (Boca Raton: CRC Press, 1982). pg. D-52.-   3. Engineering Design Handbook, Military Pyrotechnics Series. Part    1: Theory and Application. (Washington: U.S. Army Material    Command, 1967) AMCP 706-185.-   4. Krasney, John; Parker, William; Babrauskas, Vytenis. Fire    Behavior of Upholstered Furniture and Mattresses. (Norwich: Noyes    Publications, 2001).; Sundström, B., Grauers, K., and Purser, D.    Hazard Analysis in Room, Ch. 3, Fire Safety of Upholstered    Furniture—The Full Report of the European Commission Research    Program CBUF. B. Sundström, ed. (London: Interscience Communications    Ltd., 1995)

What is claimed is:
 1. A pig device comprising: an external layer; andan inner core, wherein the inner core further comprises: at least oneincendiary charge wherein each incendiary charge further comprises atleast one exothermic material; at least one ignition source coupled toeach incendiary charge wherein each ignition source is configured so asto ignite the associated incendiary charge; a plurality of thermaldispersion channels arranged within the inner core; and at least oneswitching mechanism configured so as to activate the ignition source. 2.The pig device of claim 1 wherein the external layer further comprisesan abrasive-resistant cover.
 3. The pig device of claim 1 furthercomprising at least one of an abrasive coating and a brush.
 4. The pigdevice of claim 1 wherein the thermal channels are further filled withparaffin wax wherein the paraffin wax further melts upon ignition of theincendiary charge to thereby provide for uniform thermal propagation forthe ablation process.
 5. The pig device of claim 1 wherein at least oneof the ignition sources further comprises a standard E-match electronicfirework igniter.
 6. The pig device of claim 1 wherein the switchingmechanism further comprises at least one of: a manual hardwiredswitching mechanism, a manual radio controlled switching mechanism, andan automatic pressure sensing switching mechanism.
 7. The pig device ofclaim 1 wherein at least one of the external layer and the inner corefurther comprise at least one polyurethane material.
 8. The pig deviceof claim 1 further comprising at least one radio receiver configured forsignaling the location of the pig device inside a pipeline.
 9. The pigdevice of claim 1 further comprising at least one power source.
 10. Thepig device of claim 9 wherein the power source further comprises one ormore batteries.
 11. The pig device of claim 1 further comprising one ormore LED lights configured to signal various stages of the ablationprocess.
 12. The pig device of claim 1 wherein the exothermic materialfurther comprises at least one of: barium nitrate, barium sulfate, iron(III) oxide, aluminum, and magnesium.
 13. The pig device of claim 12wherein the exothermic material further comprises barium nitrate inamounts of about 22.5% to about 27.5% by mass; barium sulfate in amountsof about 25.3% to about 33.5% by mass; iron (III) oxide in amounts ofabout 14.8% to about 19.4% by mass; aluminum in amounts of about 12.8%to about 15.8% by mass; and magnesium in amounts of about 10.4% to about13.5%.
 14. The pig device of claim 1 wherein the exothermic material isfurther housed in one or more capsules.
 15. The pig device of claim 1further comprising at least one secondary ignition material operablycoupled to the exothermic material to aid in the ignition of theincendiary charge.
 16. The pig device of claim 1 further comprising atleast one pyrotechnic igniter operably coupled to either the secondaryignition material or the exothermic material to aid in the ignition ofthe incendiary charge.
 17. A method for thermally abating a pig devicecomprising: providing a pig device comprising an external layer and aninner core, wherein the inner core comprises one or more incendiarycharges and wherein each incendiary charge further comprises one or moreexothermic materials; igniting at least one ignition source, whereineach ignition source is operably coupled to an incendiary charge tothereby release the exothermic material into one or more thermaldispersion channels; and melting the interior of each thermal dispersionchannel to thereby disperse the exothermic material through the innercore and thereby destroy the pig device.
 18. The method of claim 17further comprising igniting the ignition source via at least one of: amanual hardwired switching mechanism, a manual radio controlledswitching mechanism, and an automatic pressure sensing switchingmechanism.
 19. The method of claim 17 further comprising utilizing atleast one of a secondary ignition material and a pyrotechnic igniter toaid in the ignition of the incendiary charge.
 20. The method of claim 17wherein the exothermic material further comprises at least one of:barium nitrate, barium sulfate, iron (III) oxide, aluminum, andmagnesium.
 21. The method of claim 17 wherein the exothermic materialfurther comprises barium nitrate in amounts of about 22.5% to about27.5% by mass; barium sulfate in amounts of about 25.3% to about 33.5%by mass; iron (III) oxide in amounts of about 14.8% to about 19.4% bymass; aluminum in amounts of about 12.8% to about 15.8% by mass; andmagnesium in amounts of about 10.4% to about 13.5%.
 22. The method ofclaim 17 further comprising housing the exothermic material in at leastone capsule and wherein the ignition of the incendiary charge causes thecapsule to break and release the exothermic material.
 23. A method forretrieving a pig device which is destroyed using thermal ablationcomprising: locating the pig device within a pipeline using radiosignals detected from a radio receiver located within the pig deviceigniting at least one ignition source, wherein each ignition source isoperably coupled to an incendiary charge, to thereby release at leastone exothermic material into one or more thermal dispersion channels;melting the interior of each thermal dispersion channel to therebydisperse the exothermic material through the inner core and therebydestroy the pig device; and retrieving the pig device at the detectedlocation.
 24. The method of claim 23 further comprising igniting theignition source via at least one of: a manual hardwired switchingmechanism, a manual radio controlled switching mechanism, and anautomatic pressure sensing switching mechanism.
 25. The method of claim23 further comprising utilizing at least one of a secondary ignitionmaterial and a pyrotechnic igniter to aid in the ignition of theincendiary charge.
 26. The method of claim 23 wherein the exothermicmaterial further comprises at least one of: barium nitrate, bariumsulfate, iron (III) oxide, aluminum, and magnesium.
 27. The method ofclaim 23 wherein the exothermic material further comprises bariumnitrate in amounts of about 22.5% to about 27.5% by mass; barium sulfatein amounts of about 25.3% to about 33.5% by mass; iron (III) oxide inamounts of about 14.8% to about 19.4% by mass; aluminum in amounts ofabout 12.8% to about 15.8% by mass; and magnesium in amounts of about10.4% to about 13.5%.
 28. The method of claim 23 further comprisinghousing the exothermic material in at least one capsule and wherein theignition of the incendiary charge causes the capsule to break andrelease the exothermic material.